Wells-Dawson Type Catalyst: An Efficient, Recoverable and Reusable Solid Acid Catalyst for the Solvent-Free Synthesis of Benzodiazepines
Gustavo A. Pasquale, Diego M. Ruiz, Graciela T. Baronetti, Horacio J. Thomas, Juan C. Autino and Gustavo P. RomanelliAffiliation:
Cátedra de Química Orgánica, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. Calles 60 y 119, B1904AAN La Plata, Buenos Aires, Argentina.
AbstractVarious 3-H-1,5-benzodiazepines were prepared from the solvent-free reaction of o-phenylenediamine and substituted 1,3-diphenyl-1,3-propanedione, giving good yields of benzodiazepines. The H6P2W18O62.24H2O solid heteropolyacid, which possesses a Wells-Dawson type structure was used as catalyst both in bulk and silica-supported forms (0.1, 0.2, 0.4 and 0.6 g/g, named 0.1WDSiO2, 0.2WDSiO2, 0.4WDSiO2 and 0.6WDSiO2, respectively). The structure of the synthesized heteropolyacid was confirmed using different characterization techniques (FTIR; 31P-RMN, and potentiometric titration).
Benzodiazepines, Green chemistry, Heterogeneous catalysis, Heteropolyacid, Solvent-free reaction, Wells-Dawson structure.
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